M200 breakage

[Dave Jung]

Well I finally got my stocker out after a year and a half of work, sweat and money. Booked in for the friday test day before the first bracket race of the year. Did some driving on the return roads and set the lash etc. Went down when the lanes opened and made my first pass ever in a class car. All was good, the launch felt excellent, pulled hard in first, second pulled hard, shifted into 3rd gear and BANG!! felt a thump on the floor after the BANG. Motor kept running, shut it off and pulled over to the side. Found the driveshaft in 2 pieces, twisted in the middle. The u-joints were both intact as well. The tranny case is busted all the way around and the trans pump and converter is busted up good. So my question is, the chicken or the egg scenario, did the trans case bust, push the trans backwards and bottom out the shaft and break it? Or did the shaft break, causing the destructive forces to break the trans case. I have read about the weak bell housing area of the 200, and the braces available, but I would have thought that a 305 would be easier on them, as I know guys run them behind big blocks. After I pulled everything apart, I think the trans case went first. Any thoughts on this? Also where can I get some of the bell housing braces? thanks in advance.

Dave

[Bill Edgeworth]

Thats why McClays come with a case brace.
I'm not sure if he will sell you one if you are not a trans customer.
How hard did it leave?

[Bob Shaw]

My car did the exact same thing . I believe it was caused by the stock driveshaft whipping. I installed a transmission brace and a larger diameter custom driveshaft and never had the problem again,

[Dave Jung]

Bill,

It left good, felt good and looked good on video. It was 1.64, it was just ok.

[B Aceves]

Originally Posted by Bill Edgeworth

Thats why McClays come with a case brace.
I'm not sure if he will sell you one if you are not a trans customer.
How hard did it leave?

We use McClay, with a rubber mount also. I might add that McClay not only uses
a brace but he adds a gusset or two on the case. The failure you described is the
common 200 breakage area, but without the driveshaft failure thats a new one.
If you did have everything mounted solid its possible you might have some pinion
angle issues that added to the driveshaft failure. just a thought..

Bob Aceves
#746 E/SA
A&M motorsports

[gsa612]

What type of rear trans. mount do you have, should be stock rubber mount. Most guys with 200's (non Mclay) don't have a brace. There is a guy in B.C. Jim Mantle who does 200's I don't have his number, maybe somebody on the forum has . Sounds like there might be other issues. GSA 612

[Dave Jung]

I spoke with Jim this weekend, he was at the track and he freshened that trans not long ago. He suggested the brace. He will be building me a new one.

The rear mount was one of the urethane energy suspension models, which came in the car, with the same trans, shaft rearend etc. It was working for years that way. thanks

[Kenny Wigington]

I have a T200 without any bracing, but I do use a rubber trans mount. TurboAction 200 and never have had any problem. I was thinking you might have had a driveshaft problem, and it worked its way up stream. Mine isnt fast , by any means, but it goes 1.56-58, with a 1.54 best ever, at 50 over L weight.

[Mark Yacavone]

We have never had a brace on a T 200 and have never cracked a bellhousing .
In fact , I always cut the ears off with a skillsaw and a carbide tip blade and de- burr the edges., Factory type engine mounts with a good, solid torque strap ,and a poly type mount.
I suspect your problem started with the driveshaft. Not sure why though.
On my Omega, (350 Buick stump puller), I shortened the original 2 and 3/4 ,thin wall shaft to accommodate the 12 bolt rear, and never had a problem with that either.

[Bob Gullett]

We use a stock rear mount on our Malibu M200 and the same trans has over 1000 runs without any breakage. We have a Mark Williams driveshaft with about 1 degree pinion angle. Smooth as anything.